The format of function calling from DLL

I got a problem when calling a function from DLL. And this rule is not well document in MSDN I guess. Thus it could be a very common mistake for those who are new to DLL. I have capture the rules when trying to call a function in DLL from the client program. Lets assume a simple DLL is created, and with a FuncA() being export to the client program in that DLL.

Rule 1) When fucntion is declare using __declspec

#define __EXPORT_MODULE __declspec(dllexport)
__EXPORT_MODULE int FuncA();

The function name from Dependencies Walker is shown like below

?FuncA@@YBHWZ

Rule 2) When function is declare using extern "C"

#define __EXPORT_MODULE extern "C" __declspec(dllexport)
__EXPORT_MODULE int FuncA();

The function name from Dependencies Walker is shown like below

?FuncA

Hope this make a clear sense :)